This invention relates generally to medical devices and methods for identifying diseased tissue. More particularly, this invention relates to a cervical inspection apparatus providing magnification for visually detecting various degrees of cervical dysplasia or carcinoma in situ.
Conventionally, cervical inspection has been done primarily by taking cell samples during Papanicolaou (Pap) smear visits. The cell samples thus taken are sent to a laboratory and diagnosed to determine whether or not there is any abnormality or cancerous growth in the cervical tissue. Pap smear test are still, by far, the most commonly used cervical inspection method.
More recently, however, methods and devices have been developed for the visual inspection of the cervix. These visual inspection techniques and devices generally involve an initial treatment of the cervix with an acetic acid solution and a subsequent inspection of the cervix either with the unaided eye or with the help of a low-powered magnification device. Lighting for conventional visual inspection techniques is provided by a separate, external light source. Visual inspection with the aid of a low-powered magnification device and appropriate lighting has been proven in clinical trials to be successful in detecting moderate to severe dysplasia (CIN II and III) with a fair degree of sensitivity and specificity.
One particular prior art visual inspection method involves the use of a chemilucent tube attached to the end of a speculum and inserted into an acetic acid treated cervix to provide the required lighting. A separate binocular magnification device is used to inspect the cervix, as illuminated by the chemically created light. The chemilucent light is of a wavelength such that the differences between the normal and diseased cervical tissue can be distinguished, typically within the green spectrum.
A related prior art visual inspection method involves the use of a high-powered halogen light in combination with fiber-optic tubing for providing the appropriate lighting. Fiber-optic tubing of an appropriate hue is attached to a speculum and inserted into the cervix. The tubing is illuminated using a high-powered halogen lamp, and the cervix is then inspected using a low-powered magnification device, as in the other prior art, discussed previously.
Other prior art visual inspection methods include use of a high-powered lamp of the appropriate hue, or with an appropriate light filter to provide adequate lighting, and visual inspection of the cervix with either a separate magnification device or the unaided eye.
Despite the widespread need for accurate cervical inspection, there are a number of severe limitations to each of the prior art cervical inspection methods and/or devices. Initially, although pap smear tests are substantially accurate in determining cervical health, they do not yield immediate results, are invasive, and are fairly expensive to obtain. The test samples obtained by this invasive, hence uncomfortable, method must be sent to a lab for diagnosis and even when a lab is readily available, this process may take several weeks to complete. When labs are farther away or unavailable altogether, pap smear tests become impossible or, at least, completely impractical. Furthermore, pap smear tests require a setting that has available all the necessary equipment for taking and analyzing cervical cell samples, thus creating significant expense.
Visual inspection with the unaided eye, while readily available, inexpensive and capable of offering immediate results, is highly inaccurate and therefore the results obtained are inconsistent, and unreliable. Visual inspection without proper magnification is, for the most part, incapable of detecting moderate cases of dysplasia and even some severe cases. This method, therefore, is incapable of giving the desired and necessary level of precision. Furthermore, in order to be even minimally effective, unaided visual inspection still requires an optimal lighting condition that may be difficult to obtain, particularly in third-world countries or in rural areas of the United States and other countries.
Visual inspection with the aid of a magnification device is much more effective than unaided visual inspection in identifying unhealthy cervical tissue; however, this too requires an optimal lighting condition. High-powered lighting, as used in some of the prior art methods, is not available in many areas of the world, and hence those techniques are unavailable. In addition, traditional magnification devices are expensive (between $80-100US) and therefore do not provide a legitimate alternative for poorer regions of the world. Furthermore, the prior art visual inspection methods which do not require separate high-powered lighting are invasive and expensive. The chemilucent and fiber-optic tubes of the prior art are attached to the speculum and inserted into the cervix. These methods are therefore invasive, and uncomfortable for the patient, in practice. The chemilucent tubes further create a self-depleting light source having a limited life span. In addition, because both the chemilucent tubes and fiberoptic tubes are invasive, they are not safely reusable. These tubes therefore require replacement after every use and are expensive (about $6US each for the chemilucent tubes). Additionally, the halogen light used to illuminate the fiber-optic tubing should be high-powered to be effective and will therefore be impractical or unavailable in many settings where cervical inspection is needed.
A substantial need therefore exists in the industry for a cost-effective, non-invasive, cervical inspection apparatus and method capable of yielding immediate results with substantial accuracy, and further capable of being performed in areas with limited lighting capabilities or lacking modern hospital facilities or laboratories.